1. Field of the Invention
This invention relates to side mirror assemblies for motor vehicles. More particularly, the invention relates to side mirror assemblies having spotting mirrors to minimize the effects of blind spots in motor vehicles.
2. Description of the Related Art
In motor vehicles, side mirror assemblies typically enable the driver to conveniently view rearward and sideward portions of the vehicle to check for obstacles or other vehicles. Typically, the mirror assembly includes a base which attaches to the motor vehicle and supports a housing. Within the housing, a backing supports a reflective element. The reflective element typically adjusts so that various rearward and sideward portions around the motor vehicle may be viewed by the driver. The reflective elements or the mirrors are typically one uniform surface within the assemblies.
Some side mirror assemblies for motor vehicles are one uniform surface. U.S. Pat. No. 7,097,312 discloses a compound automotive rear view mirror. This composite mirror facilitates the reduction or elimination of blind zone due to the configuration of the composite mirror. More specifically, the composite mirror includes a glass main mirror and a convex auxiliary blind zone viewing mirror in one corner thereof. While these composite mirror configurations aid in the reduction or elimination of the blind zone or blind spot of a motor vehicle, these composite mirror configurations are difficult to maintain. Typically, the auxiliary mirror is glued to the primary mirror. The adhesive used to bond the two mirrors together may fail. Helping the failure of the adhesive, the use of devices such as scrapers to remove frost and debris from the mirror assembly weakens the adhesion between the two mirrors.
U.S. Pat. No. 7,420,756 also discloses a composite mirror within an automotive rear view mirror. This invention discloses a reflective element comprised of a substrate that is a molded, cast, or extruded, or cut from sheet and is a polymeric resin material. Optionally a film is disposed onto the substrate to provide an anti-abrasion layer. This film may be a glass or resin material and may also have a reflective coating applied to it. The reflective coating may be metallic. This patent does not, however, disclose a metallic substrate for the reflective surface. And while a portion of the mirror (18d) does not define a flat plane, this composite mirror does not have flanges extending around any portion of the periphery, nor does it disclose any channels in a backing plate to receive flanges formed on the back side of the composite mirror.
And finally, costs for such mirror assemblies are greatly increased. The production and inventory costs are increased due to the requirement of having two mirror elements for each side mirror assembly as in U.S. Pat. No. 7,097,312. In addition, labor costs associated with the production of the mirror assemblies and properly aligning the auxiliary mirror with respect to the primary mirror significantly increases the cost in manufacturing a side mirror assembly. The technical difficulties and complex equipment increase the costs and complexities of manufacture if one were to employ the inventions disclosed in U.S. Pat. No. 7,420,756 to adhere anti-abrasion films or layers of glass to a molded, cast, extruded or die cut sheet. Finally, it is technically difficult to uniformly heat composite mirrors if the mirror assembly has a heated glass feature.